On 06/23/20 21:44, Andres Freund wrote:
> I think that's way harder than what you make it sound here. The locking
> for shm_mq doesn't really work inside a process. In contrast to the
> single threaded case something like a volatile write to
> ParallelMessagePending doesn't guarantee much, because there's no
> guaranteed memory ordering between threads. And more.
It occurred to me after I sent the message this morning that my suggestion
(2) could subsume (1). And requires nothing more than a single volatile
write of a boolean, and getting called back at a convenient time on the
single main thread.
So perhaps I shouldn't have suggested (1) at all - just muddies the waters.
Regards,
-Chap